/Engine/Source/Runtime/MovieScene/Public/EntitySystem/MovieSceneEntitySystemLinker.h
Add an extension to this linker.
template<typename ExtensionType> void AddExtension ( [UE::MovieScene::TEntitySystemLinkerExtensionID](API\Runtime\MovieScene\EntitySystem\TEntitySystemLinkerExtensionID)< ExtensionType > InID, ExtensionType * InExtension )